1. Field of the Invention
The present invention relates to the field of three dimensional modeling; and more particularly to the creation of three dimensional models from a two dimensional image.
2. Description of Related Art
Researchers have attempted to create three dimensional models of scenes based on two dimensional photographs. The resulting model helps to provide virtual environments or valuable visualization tools.
Some prior techniques have used architectural plans, CAD designs, and other human input. Such creation of three dimensional models can be expensive and time consuming. Further, such computer generated models may not accurately reflect the look of the scene which is being modeled.
Attempts have been made to create models from two dimensional photographs. Some such techniques use stereo computational techniques based on multiple images of the scene to be modeled. Such techniques require more than one photograph of the scene to be modeled.
One modeling system is described in an article entitled "Modeling and Rendering Architecture From Photographs: A Hybrid Geometry- and Image-Based Approach," Technical Report UCB//csd-96-893, Jan. 19, 1996 by P. Debevec, C. Taylor, J. Malik. Another approach is described in "Semiautomatic 3-D Model Extraction From Uncalibrated 2-D Camera Views," MIT Media Laboratory by S. Becker and V. Bove.
"Constraints" are relationships between aspects of items in a scene, such as a parallel relationship between surfaces. Using constraints, researchers have attempted to solve for three dimensional models of scenes.
One method for extracting a three dimensional model of an object based on image data is described in U.S. Pat. No. 5,633,995 by McClain. In McClain, multiple cameras are shown to acquire information about a scene.
One problem encountered in three dimensional modeling from two dimensional photographs relates to distortion in the image due to a camera's characteristics.
A photograph from which a model is to be created may lack significant indications of physical structure that would allow a three dimensional model to be easily created from the photograph. There may be a lack of sufficient number of surfaces visible that have knowable orientations and interconnectivity relationships. Such an under-constrained situation may lead to solutions for the camera model and scene model that may be consistent with the available data but which yield some aspects that may not appear correct to a human observer.
Even in over-constrained cases, errors in the determination of image positions, as well as errors in the constraints supplied, may lead to a solution that yields an image that does not appear perfectly accurate.
Prior techniques of creating three dimensional models have the disadvantage of requiring extensive information about scene geometry that may not be available in the images provided. Further, using models created by prior techniques, resulting projections of images may not appear correct. Thus, there is a need for an improved method of creation of three dimensional models.